Pro-/anti-inflammatory cytokine gene polymorphisms and chronic kidney disease: a cross-sectional study

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to explore the associations between common potential functional promoter polymorphisms in pro-/anti-inflammatory cytokine genes and kidney function/chronic kidney disease (CKD) prevalence in a large Japanese population.</p> <p>Methods</p> <p>A total of 3,323 subjects aged 35-69 were genotyped for all 10 single nucleotide polymorphisms (SNPs) in the promoter regions of candidate genes with minor allele frequencies of > 0.100 in Japanese populations. The estimated glomerular filtration rate (eGFR) and CKD prevalence (eGFR < 60 ml/min/1.73 m²) of the subjects were compared among the genotypes.</p> <p>Results</p> <p>A higher eGFR and lower prevalence of CKD were observed for the homozygous variants of <it>IL4 </it>-33CC (high IL-4 [anti-inflammatory cytokine]-producing genotype) and <it>IL6 </it>-572GG (low IL-6 [pro-inflammatory cytokine]-producing genotype). Subjects with <it>IL4 </it>CC + <it>IL6 </it>GG showed the highest mean eGFR (79.1 ml/min/1.73 m²) and lowest CKD prevalence (0.0%), while subjects carrying <it>IL4 </it>TT + <it>IL6 </it>CC showed the lowest mean eGFR (73.4 ml/min/1.73 m²) and highest CKD prevalence (17.9%).</p> <p>Conclusions</p> <p>The functional promoter polymorphisms <it>IL4 </it>T-33C (rs2070874) and <it>IL6 </it>C-572G (rs1800796), which are the only SNPs that affect the IL-4 and IL-6 levels in Japanese subjects, were associated with kidney function and CKD prevalence in a large Japanese population.</p